Fujitsu Laboratories recently developed a technology that can embed data in a color print image that is invisible to the naked eye. Using this technique, 12 digits such as a telephone number and a URL conversion code can be embedded in a minimum 1 cm x 1 cm image. According to Noda Shinoda, a researcher at the company’s Peripheral Systems Research Institute, “there is no need for special space like barcodes”.

Use mobile phone camera to read images

The technology recodes the original image and the data that needs to be embedded before printing. After the printed image is read through a device such as a mobile phone camera, it can be used to make a call or visit a website based on a URL using a dedicated software for restoration. Test results using Fujitsu's own PDA showed that the image reading time was 0.4 seconds. "It is estimated that ordinary portable terminals can be controlled under 1 second."

The key to this technique is to divide the original image into multiple small areas, and then embed the data information in the form of "yellow dots" according to the level information of the images in the adjacent areas. Specifically, the image is divided into regions less than 0.8 mm square, the average color gradation of each image block is analyzed, and information is embedded in a portion with a low color tone. By using a yellow area where the image quality is not easily perceived by the human eye and a small area less than 0.8 mm square, data can be stored in an invisible manner.

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Another advantage is that the read performance is not affected by the performance of the printing device. For example, when the entire print image is darkened or faded due to the performance and state of the printing apparatus, there is little influence on the read performance because of the small influence on the relative color difference between the small areas. Can also use the home color printer to print.

Applications contemplated by this technology include making a phone call by reading a photo on a business card, downloading a ringtone from a CD package, or obtaining store information through a store photo published in a magazine. About production time and sales methods will be further explored in the future.